This invention relates particularly to electrically operated heating devices for beverage brewing apparatus, such as coffee makers, wherein liquid, such as water, is heated as it flows through a passageway. Heretofore, such a passageway has been defined by a metallic tube mechanically mounted in a groove or channel formed in a supporting base, usually of cast metal such as aluminum. The base is usually formed to provide a second channel for a heating element in closely spaced relation to the liquid conducting tube, or the heating element is embedded in the base during casting or molding of the base. The mechanical mounting of the liquid conducting tube is usually accomplished by staking or peening the metal of the base against the tube at spaced apart points, and has resulted in rather unsatisfactory heat transfer from the heating element to liquid flowing through the tube.
An important object of this invention is the provision of a heating device for liquid including an extruded metallic body defining a pair of laterally spaced holes extending longitudinally therethrough, and a heating element extending through one of the holes, and including an arrangement wherein the heating element has tight surface engagement with the body for efficient transfer to the other one of the holes.
Another object of this invention is the provision of a heating device which is simple and inexpensive to produce.
Another object of this invention is the provision of a novel method for producing a heating device for liquids.
To these ends, I provide a heating device comprising an elongated extruded body of metal having high heat conductivity, the body defining a pair of spaced parallel holes extending longitudinally therethrough, and an elongated heating element extending longitudinally through one of the holes, the other one of the holes providing a passageway for liquid to be heated. The body and heating element are curved intermediate their ends about an axis extending in a direction transversely with respect to the body into generally U-shape. The body further defines a transversely opening channel that extends longitudinally of the body for reception of a second heating element, the liquid receiving passageway being disposed between the heating elements.
In carrying out the method for producing the heating device of this invention, I provide the steps of, extruding metal, such as aluminum, to provide a generally straight elongated body having a pair of spaced parallel holes extending longitudinally through the body, inserting an elongated heating element through one of the holes for snug fit therein, and thereafter bending the body and heating element intermediate their ends, about an axis extending transversely with respect to the body, into generally U-shape.